Nigel de Grey , UK, member of the Room 40 British codebreaking team who played an important role in the decryption of the Zimmermann Telegram during WWI
Elizebeth Friedman, US, wife of William F, and cryptographer in her own right for the Coast Guard, Treasury Department, and assorted other US Government agencies in the 1920s and 1930s. Co-author of the most respected book on cyphers in Shakespeare. The spelling of her name is correct with three 'e's.
William F. Friedman, US, introduced statistical methods into cryptography; some would describe him as the founder of modern cryptography. Cryptography and genetics director at the Riverbank Laboratories before WWI, wrote extensively on cryptographic theory and practice, and became the US Army's chief (and for some time only) cryptographer, patented several cryptography related inventions some of which are still secret 60+ years later, including some aspects of the SIGABA machine. Co-author of the most respected book on cyphers in Shakespeare.
Dilwyn Knox, UK, Classics scholar and eccentric; WWI Room 40 member who stayed with cryptography between the Wars, becoming the chief cryptanalyst of the GC&CS before WWII. Broke commercial Enigma. Famous for solving problems in the bath.
Leo Marks, UK, World War II cryptographer and SOE cryptography director, playwright, author of Between Silk and Cyanide.
John Joseph Rochefort, US, mustang Navy officer (ie, ex enlisted) who early specialized in cryptography and languages, following Safford. A Japanese speaker. Became director of Station Hypo in Hawaii which made major contributions to the break into JN-25 after the attack on Pearl Harbor which led to the successful ambush at Midway. Casualty of power struggle within USN cryptography organization, was forced out of cryptography, and finished WWII in command of a dry dock in California. Honored posthumously for his Hawaiian cryptography work.
Frank Rowlett, US, leader of the team that broke Purple, contributor to the design of SIGABA. One of William Friedman's first three employees at the SIS.
Laurance Safford, US, chief cryptographer for the US Navy for 2 decades+. Also its first. Pioneered what became OP-20-G in WWII. One of the first Japanese speaking officers in the US Navy.
Abraham Sinkov, US, one of William Freidman's first three employees at the SIS in the 1930s.
John Tiltman, UK, British Army officer from Scotland, talented cryptographer/cryptanalyst. Contributed significantly before WWII in the era of hand cryptanalysis and during/after WWII in the era of machine assisted cryptanalysis. Worked at Bletchley Park and GCHQ.
Alan Mathison Turing, UK, one of the most original minds of the 20th century and one the chief cryptographers at Bletchley Park during World War II. Made major contributions to the theory of computation, and can even be regarded as its originator. Made major contributions to the engineering design and development of early computer hardware and software at the NPL and later at the University of Manchester.
Gordon Welchman , UK, Turing's associate in the Naval Enigma Hut at Bletchley Park during WWII. Made major contributions to its cryptanalysis.
Herbert Yardley, US, best known for his book "The American Black Chamber". Gambler, raconteur, roving cryptographer for hire (eg, Canada, Japan) after MI8 was closed.
Carlisle Adams , Can, co-developer of the CAST series of encryption algorithms, one of which was an AES contest participant. Initials accidentally correspond to first 2 letters of CAST. See also Stafford Tavares .
Stefan Brands , Netherlands and CAN ?, Associate Professor in Computer Science, McGill University. Author of work on digital credentials.
Dan Boneh , Israel and US ?, Associate Professor, Applied Cryptography Group, Computer Science and Electrical Engineering, Stanford University. With G. Durfee, coauthor of the Cryptanalysis of RSA with private key d less than N^0.292. See http://crypto.stanford.edu/~dabo/
James Ellis, UK, staff member of GCHQ who proved the possibility of 'non-secret' encryption. That proof led Clifford Cocks to invent (first) what has become known as the RSA encryption algorithm, and Malcolm Williamson (note: not the composer) to invent (first) what has become known as the Diffie-Hellmanprotocol.
Stafford Tavares , Can, co-developer of the CAST series of encryption algorithms, one of which was an AES contest participant. Initials accidentally correspond to last 2 letters of CAST. See also Carlisle Adams .